diff --git a/wherehows-web/app/services/user-lookup.js b/wherehows-web/app/services/user-lookup.js
new file mode 100644
index 0000000000..8b252a9e03
--- /dev/null
+++ b/wherehows-web/app/services/user-lookup.js
@@ -0,0 +1,84 @@
+import Ember from 'ember';
+
+const {
+  isEmpty,
+  Service,
+  $: { getJSON }
+} = Ember;
+const partyEntitiesUrl = '/api/v1/party/entities';
+
+const cache = {
+  // Cache containing results from the last request to partyEntities api
+  partyEntities: null
+};
+
+/**
+ * Async request for partyEntities. Caches the value from the initial request
+ * @return {Promise.<Object|void>}
+ */
+const getLDAPUsers = () =>
+  new Promise(resolve => {
+    const cachedResults = cache.partyEntities;
+
+    // Resolve with cachedResults if this has been previously requested
+    if (!isEmpty(cachedResults)) {
+      return resolve(cachedResults);
+    }
+
+    // Cast $.getJSON to native Promise
+    Promise.resolve(getJSON(partyEntitiesUrl))
+      .then(({ status, userEntities = [] }) => {
+        if (status === 'ok' && userEntities.length) {
+          /**
+           * @type {Object} userEntitiesMaps hash of userEntities: label -> displayName
+           */
+          const userEntitiesMaps = userEntities.reduce(
+            (map, { label, displayName }) => ((map[label] = displayName), map),
+            {}
+          );
+
+          return ({
+            userEntities,
+            userEntitiesMaps,
+            userEntitiesSource: Object.keys(userEntitiesMaps)
+          });
+        }
+      })
+      .then(results => cache.partyEntities = results)
+      .then(resolve);
+  });
+
+/**
+ * Takes a userNameQuery query and find userNames that match by starting with
+ *  the pattern
+ * @param {String} userNameQuery pattern to search for
+ * @param {Function} syncResults callback
+ * @param {Function} asyncResults callback
+ */
+const ldapResolver = (userNameQuery, syncResults, asyncResults) => {
+  const regex = new RegExp(`^${userNameQuery}.*`, 'i');
+
+  getLDAPUsers()
+    .then(({ userEntitiesSource = {} }) =>
+      userEntitiesSource.filter(entity => regex.test(entity)))
+    .then(asyncResults);
+};
+
+/**
+ * For a given userName, find the userEntity object that contains the userName
+ * @param {String} userName the unique userName
+ * @return {Promise.<TResult|null>} resolves with the userEntity or null otherwise
+ */
+const getPartyEntityWithUserName = userName => {
+  return getLDAPUsers()
+    .then(
+      ({ userEntities }) => userEntities.find(({ label }) => label === userName) ||
+      null
+    );
+};
+
+export default Service.extend({
+  getPartyEntityWithUserName,
+  userNamesResolver: ldapResolver,
+  fetchUserNames: getLDAPUsers
+});
diff --git a/wherehows-web/tests/unit/services/user-lookup-test.js b/wherehows-web/tests/unit/services/user-lookup-test.js
new file mode 100644
index 0000000000..5c37f17ebd
--- /dev/null
+++ b/wherehows-web/tests/unit/services/user-lookup-test.js
@@ -0,0 +1,12 @@
+import { moduleFor, test } from 'ember-qunit';
+
+moduleFor('service:user-lookup', 'Unit | Service | user lookup', {
+  // Specify the other units that are required for this test.
+  // needs: ['service:foo']
+});
+
+// Replace this with your real tests.
+test('it exists', function(assert) {
+  let service = this.subject();
+  assert.ok(service);
+});